• Made by impact resistant polymer, provides light weight and resists operational abuse
  • Spring-loaded flip up sight easily activated from either side or by pressing the top
  • Detent and spring pressure keeps sight erect but allows for unobstructed folding under impact, etc.
  • Can be install on any Mil-Spec 1913 Picatinny and STANAG 4694 rail
  • Provides the same height-over-bore as standard A2 irons
  • Protective wings shield the spring-locking A2 front sight post
  • Elevation adjustment tool included, but most aftermarket A2 front sight adjustment tools may be used as well
  • The Magpul Back Up Front Sight (MBUS) Gen2 comes in: Black, Flat Dark Earth, and OD Green
  • Made in the U.S.A.


  • Material: Polymer
  • Finish: Black, Flat Dark Earth, or OD Green
  • Weight: 1.2 oz.
  • Height Above Rail, Stowed: ~0.51"
  • Length, Stowed: 2.6"
  • Length, Deployed: 1.5"


  • Any firearm with top Picatinny top rail

**NOT recommend to mount on a railed gas block due to excess heat issues.

**Sight is designed to work on same plane rail systems only. Will not work with a railed gas block that is higher or lower than the receiver.


  • 1x Magpul Flip-Up Front Sight
  • 1x Front Sight Adjustment Tool


The Magpul Back Up Sight (MBUS) is a must for any AR-15/AR-10 owner. Constructed from virtually indestructible polymer, these sights can serve as a back up to your scope or red dot. They also make an excellent light weight primary sight.

Since the Magpul MBUS front sight offers the same height-over-bore distance as the standard A2 iron sights, AR-15/AR-10 devotees will feel right at home with these sights. The sight post is protected by two "wings" on either side to prevent it from being damaged or bumped out of zero.

When the sight is not in use, it can be folded down. When it is needed again, you can instantly pop this spring loaded sight back into position with no loss of zero! The MBUS is optimized for the AR-15 and M-16 family of rifles, but it will also fit any weapon that features a 1913 Picatinny rail.

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Reviews (3)

  • Works great shipped fast

    Posted by Scott on 8th May 2020

    Works great shipped fast

  • Magpul Back Up Front Sight (MBUS)

    Posted by PK on 10th Oct 2019

    Functional and of good quality for being plastic.

  • Magpul Back Up Front Sight (MBUS) Gen2

    Posted by Unknown on 22nd Jul 2016

    Great back up sights if your primary optics fail. Easy to install and adjust within minutes. Have these installed on all of my AR builds.

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